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[mirror_ubuntu-artful-kernel.git] / fs / xfs / libxfs / xfs_attr_remote.c
1 /*
2 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
3 * Copyright (c) 2013 Red Hat, Inc.
4 * All Rights Reserved.
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License as
8 * published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it would be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
18 */
19 #include "xfs.h"
20 #include "xfs_fs.h"
21 #include "xfs_shared.h"
22 #include "xfs_format.h"
23 #include "xfs_log_format.h"
24 #include "xfs_trans_resv.h"
25 #include "xfs_bit.h"
26 #include "xfs_mount.h"
27 #include "xfs_da_format.h"
28 #include "xfs_da_btree.h"
29 #include "xfs_inode.h"
30 #include "xfs_alloc.h"
31 #include "xfs_trans.h"
32 #include "xfs_inode_item.h"
33 #include "xfs_bmap.h"
34 #include "xfs_bmap_util.h"
35 #include "xfs_attr.h"
36 #include "xfs_attr_leaf.h"
37 #include "xfs_attr_remote.h"
38 #include "xfs_trans_space.h"
39 #include "xfs_trace.h"
40 #include "xfs_cksum.h"
41 #include "xfs_buf_item.h"
42 #include "xfs_error.h"
43
44 #define ATTR_RMTVALUE_MAPSIZE 1 /* # of map entries at once */
45
46 /*
47 * Each contiguous block has a header, so it is not just a simple attribute
48 * length to FSB conversion.
49 */
50 int
51 xfs_attr3_rmt_blocks(
52 struct xfs_mount *mp,
53 int attrlen)
54 {
55 if (xfs_sb_version_hascrc(&mp->m_sb)) {
56 int buflen = XFS_ATTR3_RMT_BUF_SPACE(mp, mp->m_sb.sb_blocksize);
57 return (attrlen + buflen - 1) / buflen;
58 }
59 return XFS_B_TO_FSB(mp, attrlen);
60 }
61
62 /*
63 * Checking of the remote attribute header is split into two parts. The verifier
64 * does CRC, location and bounds checking, the unpacking function checks the
65 * attribute parameters and owner.
66 */
67 static bool
68 xfs_attr3_rmt_hdr_ok(
69 void *ptr,
70 xfs_ino_t ino,
71 uint32_t offset,
72 uint32_t size,
73 xfs_daddr_t bno)
74 {
75 struct xfs_attr3_rmt_hdr *rmt = ptr;
76
77 if (bno != be64_to_cpu(rmt->rm_blkno))
78 return false;
79 if (offset != be32_to_cpu(rmt->rm_offset))
80 return false;
81 if (size != be32_to_cpu(rmt->rm_bytes))
82 return false;
83 if (ino != be64_to_cpu(rmt->rm_owner))
84 return false;
85
86 /* ok */
87 return true;
88 }
89
90 static bool
91 xfs_attr3_rmt_verify(
92 struct xfs_mount *mp,
93 void *ptr,
94 int fsbsize,
95 xfs_daddr_t bno)
96 {
97 struct xfs_attr3_rmt_hdr *rmt = ptr;
98
99 if (!xfs_sb_version_hascrc(&mp->m_sb))
100 return false;
101 if (rmt->rm_magic != cpu_to_be32(XFS_ATTR3_RMT_MAGIC))
102 return false;
103 if (!uuid_equal(&rmt->rm_uuid, &mp->m_sb.sb_meta_uuid))
104 return false;
105 if (be64_to_cpu(rmt->rm_blkno) != bno)
106 return false;
107 if (be32_to_cpu(rmt->rm_bytes) > fsbsize - sizeof(*rmt))
108 return false;
109 if (be32_to_cpu(rmt->rm_offset) +
110 be32_to_cpu(rmt->rm_bytes) > XATTR_SIZE_MAX)
111 return false;
112 if (rmt->rm_owner == 0)
113 return false;
114
115 return true;
116 }
117
118 static void
119 xfs_attr3_rmt_read_verify(
120 struct xfs_buf *bp)
121 {
122 struct xfs_mount *mp = bp->b_target->bt_mount;
123 char *ptr;
124 int len;
125 xfs_daddr_t bno;
126 int blksize = mp->m_attr_geo->blksize;
127
128 /* no verification of non-crc buffers */
129 if (!xfs_sb_version_hascrc(&mp->m_sb))
130 return;
131
132 ptr = bp->b_addr;
133 bno = bp->b_bn;
134 len = BBTOB(bp->b_length);
135 ASSERT(len >= blksize);
136
137 while (len > 0) {
138 if (!xfs_verify_cksum(ptr, blksize, XFS_ATTR3_RMT_CRC_OFF)) {
139 xfs_buf_ioerror(bp, -EFSBADCRC);
140 break;
141 }
142 if (!xfs_attr3_rmt_verify(mp, ptr, blksize, bno)) {
143 xfs_buf_ioerror(bp, -EFSCORRUPTED);
144 break;
145 }
146 len -= blksize;
147 ptr += blksize;
148 bno += BTOBB(blksize);
149 }
150
151 if (bp->b_error)
152 xfs_verifier_error(bp);
153 else
154 ASSERT(len == 0);
155 }
156
157 static void
158 xfs_attr3_rmt_write_verify(
159 struct xfs_buf *bp)
160 {
161 struct xfs_mount *mp = bp->b_target->bt_mount;
162 int blksize = mp->m_attr_geo->blksize;
163 char *ptr;
164 int len;
165 xfs_daddr_t bno;
166
167 /* no verification of non-crc buffers */
168 if (!xfs_sb_version_hascrc(&mp->m_sb))
169 return;
170
171 ptr = bp->b_addr;
172 bno = bp->b_bn;
173 len = BBTOB(bp->b_length);
174 ASSERT(len >= blksize);
175
176 while (len > 0) {
177 struct xfs_attr3_rmt_hdr *rmt = (struct xfs_attr3_rmt_hdr *)ptr;
178
179 if (!xfs_attr3_rmt_verify(mp, ptr, blksize, bno)) {
180 xfs_buf_ioerror(bp, -EFSCORRUPTED);
181 xfs_verifier_error(bp);
182 return;
183 }
184
185 /*
186 * Ensure we aren't writing bogus LSNs to disk. See
187 * xfs_attr3_rmt_hdr_set() for the explanation.
188 */
189 if (rmt->rm_lsn != cpu_to_be64(NULLCOMMITLSN)) {
190 xfs_buf_ioerror(bp, -EFSCORRUPTED);
191 xfs_verifier_error(bp);
192 return;
193 }
194 xfs_update_cksum(ptr, blksize, XFS_ATTR3_RMT_CRC_OFF);
195
196 len -= blksize;
197 ptr += blksize;
198 bno += BTOBB(blksize);
199 }
200 ASSERT(len == 0);
201 }
202
203 const struct xfs_buf_ops xfs_attr3_rmt_buf_ops = {
204 .verify_read = xfs_attr3_rmt_read_verify,
205 .verify_write = xfs_attr3_rmt_write_verify,
206 };
207
208 STATIC int
209 xfs_attr3_rmt_hdr_set(
210 struct xfs_mount *mp,
211 void *ptr,
212 xfs_ino_t ino,
213 uint32_t offset,
214 uint32_t size,
215 xfs_daddr_t bno)
216 {
217 struct xfs_attr3_rmt_hdr *rmt = ptr;
218
219 if (!xfs_sb_version_hascrc(&mp->m_sb))
220 return 0;
221
222 rmt->rm_magic = cpu_to_be32(XFS_ATTR3_RMT_MAGIC);
223 rmt->rm_offset = cpu_to_be32(offset);
224 rmt->rm_bytes = cpu_to_be32(size);
225 uuid_copy(&rmt->rm_uuid, &mp->m_sb.sb_meta_uuid);
226 rmt->rm_owner = cpu_to_be64(ino);
227 rmt->rm_blkno = cpu_to_be64(bno);
228
229 /*
230 * Remote attribute blocks are written synchronously, so we don't
231 * have an LSN that we can stamp in them that makes any sense to log
232 * recovery. To ensure that log recovery handles overwrites of these
233 * blocks sanely (i.e. once they've been freed and reallocated as some
234 * other type of metadata) we need to ensure that the LSN has a value
235 * that tells log recovery to ignore the LSN and overwrite the buffer
236 * with whatever is in it's log. To do this, we use the magic
237 * NULLCOMMITLSN to indicate that the LSN is invalid.
238 */
239 rmt->rm_lsn = cpu_to_be64(NULLCOMMITLSN);
240
241 return sizeof(struct xfs_attr3_rmt_hdr);
242 }
243
244 /*
245 * Helper functions to copy attribute data in and out of the one disk extents
246 */
247 STATIC int
248 xfs_attr_rmtval_copyout(
249 struct xfs_mount *mp,
250 struct xfs_buf *bp,
251 xfs_ino_t ino,
252 int *offset,
253 int *valuelen,
254 __uint8_t **dst)
255 {
256 char *src = bp->b_addr;
257 xfs_daddr_t bno = bp->b_bn;
258 int len = BBTOB(bp->b_length);
259 int blksize = mp->m_attr_geo->blksize;
260
261 ASSERT(len >= blksize);
262
263 while (len > 0 && *valuelen > 0) {
264 int hdr_size = 0;
265 int byte_cnt = XFS_ATTR3_RMT_BUF_SPACE(mp, blksize);
266
267 byte_cnt = min(*valuelen, byte_cnt);
268
269 if (xfs_sb_version_hascrc(&mp->m_sb)) {
270 if (!xfs_attr3_rmt_hdr_ok(src, ino, *offset,
271 byte_cnt, bno)) {
272 xfs_alert(mp,
273 "remote attribute header mismatch bno/off/len/owner (0x%llx/0x%x/Ox%x/0x%llx)",
274 bno, *offset, byte_cnt, ino);
275 return -EFSCORRUPTED;
276 }
277 hdr_size = sizeof(struct xfs_attr3_rmt_hdr);
278 }
279
280 memcpy(*dst, src + hdr_size, byte_cnt);
281
282 /* roll buffer forwards */
283 len -= blksize;
284 src += blksize;
285 bno += BTOBB(blksize);
286
287 /* roll attribute data forwards */
288 *valuelen -= byte_cnt;
289 *dst += byte_cnt;
290 *offset += byte_cnt;
291 }
292 return 0;
293 }
294
295 STATIC void
296 xfs_attr_rmtval_copyin(
297 struct xfs_mount *mp,
298 struct xfs_buf *bp,
299 xfs_ino_t ino,
300 int *offset,
301 int *valuelen,
302 __uint8_t **src)
303 {
304 char *dst = bp->b_addr;
305 xfs_daddr_t bno = bp->b_bn;
306 int len = BBTOB(bp->b_length);
307 int blksize = mp->m_attr_geo->blksize;
308
309 ASSERT(len >= blksize);
310
311 while (len > 0 && *valuelen > 0) {
312 int hdr_size;
313 int byte_cnt = XFS_ATTR3_RMT_BUF_SPACE(mp, blksize);
314
315 byte_cnt = min(*valuelen, byte_cnt);
316 hdr_size = xfs_attr3_rmt_hdr_set(mp, dst, ino, *offset,
317 byte_cnt, bno);
318
319 memcpy(dst + hdr_size, *src, byte_cnt);
320
321 /*
322 * If this is the last block, zero the remainder of it.
323 * Check that we are actually the last block, too.
324 */
325 if (byte_cnt + hdr_size < blksize) {
326 ASSERT(*valuelen - byte_cnt == 0);
327 ASSERT(len == blksize);
328 memset(dst + hdr_size + byte_cnt, 0,
329 blksize - hdr_size - byte_cnt);
330 }
331
332 /* roll buffer forwards */
333 len -= blksize;
334 dst += blksize;
335 bno += BTOBB(blksize);
336
337 /* roll attribute data forwards */
338 *valuelen -= byte_cnt;
339 *src += byte_cnt;
340 *offset += byte_cnt;
341 }
342 }
343
344 /*
345 * Read the value associated with an attribute from the out-of-line buffer
346 * that we stored it in.
347 */
348 int
349 xfs_attr_rmtval_get(
350 struct xfs_da_args *args)
351 {
352 struct xfs_bmbt_irec map[ATTR_RMTVALUE_MAPSIZE];
353 struct xfs_mount *mp = args->dp->i_mount;
354 struct xfs_buf *bp;
355 xfs_dablk_t lblkno = args->rmtblkno;
356 __uint8_t *dst = args->value;
357 int valuelen;
358 int nmap;
359 int error;
360 int blkcnt = args->rmtblkcnt;
361 int i;
362 int offset = 0;
363
364 trace_xfs_attr_rmtval_get(args);
365
366 ASSERT(!(args->flags & ATTR_KERNOVAL));
367 ASSERT(args->rmtvaluelen == args->valuelen);
368
369 valuelen = args->rmtvaluelen;
370 while (valuelen > 0) {
371 nmap = ATTR_RMTVALUE_MAPSIZE;
372 error = xfs_bmapi_read(args->dp, (xfs_fileoff_t)lblkno,
373 blkcnt, map, &nmap,
374 XFS_BMAPI_ATTRFORK);
375 if (error)
376 return error;
377 ASSERT(nmap >= 1);
378
379 for (i = 0; (i < nmap) && (valuelen > 0); i++) {
380 xfs_daddr_t dblkno;
381 int dblkcnt;
382
383 ASSERT((map[i].br_startblock != DELAYSTARTBLOCK) &&
384 (map[i].br_startblock != HOLESTARTBLOCK));
385 dblkno = XFS_FSB_TO_DADDR(mp, map[i].br_startblock);
386 dblkcnt = XFS_FSB_TO_BB(mp, map[i].br_blockcount);
387 error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp,
388 dblkno, dblkcnt, 0, &bp,
389 &xfs_attr3_rmt_buf_ops);
390 if (error)
391 return error;
392
393 error = xfs_attr_rmtval_copyout(mp, bp, args->dp->i_ino,
394 &offset, &valuelen,
395 &dst);
396 xfs_buf_relse(bp);
397 if (error)
398 return error;
399
400 /* roll attribute extent map forwards */
401 lblkno += map[i].br_blockcount;
402 blkcnt -= map[i].br_blockcount;
403 }
404 }
405 ASSERT(valuelen == 0);
406 return 0;
407 }
408
409 /*
410 * Write the value associated with an attribute into the out-of-line buffer
411 * that we have defined for it.
412 */
413 int
414 xfs_attr_rmtval_set(
415 struct xfs_da_args *args)
416 {
417 struct xfs_inode *dp = args->dp;
418 struct xfs_mount *mp = dp->i_mount;
419 struct xfs_bmbt_irec map;
420 xfs_dablk_t lblkno;
421 xfs_fileoff_t lfileoff = 0;
422 __uint8_t *src = args->value;
423 int blkcnt;
424 int valuelen;
425 int nmap;
426 int error;
427 int offset = 0;
428
429 trace_xfs_attr_rmtval_set(args);
430
431 /*
432 * Find a "hole" in the attribute address space large enough for
433 * us to drop the new attribute's value into. Because CRC enable
434 * attributes have headers, we can't just do a straight byte to FSB
435 * conversion and have to take the header space into account.
436 */
437 blkcnt = xfs_attr3_rmt_blocks(mp, args->rmtvaluelen);
438 error = xfs_bmap_first_unused(args->trans, args->dp, blkcnt, &lfileoff,
439 XFS_ATTR_FORK);
440 if (error)
441 return error;
442
443 args->rmtblkno = lblkno = (xfs_dablk_t)lfileoff;
444 args->rmtblkcnt = blkcnt;
445
446 /*
447 * Roll through the "value", allocating blocks on disk as required.
448 */
449 while (blkcnt > 0) {
450 int committed;
451
452 /*
453 * Allocate a single extent, up to the size of the value.
454 *
455 * Note that we have to consider this a data allocation as we
456 * write the remote attribute without logging the contents.
457 * Hence we must ensure that we aren't using blocks that are on
458 * the busy list so that we don't overwrite blocks which have
459 * recently been freed but their transactions are not yet
460 * committed to disk. If we overwrite the contents of a busy
461 * extent and then crash then the block may not contain the
462 * correct metadata after log recovery occurs.
463 */
464 xfs_bmap_init(args->flist, args->firstblock);
465 nmap = 1;
466 error = xfs_bmapi_write(args->trans, dp, (xfs_fileoff_t)lblkno,
467 blkcnt, XFS_BMAPI_ATTRFORK, args->firstblock,
468 args->total, &map, &nmap, args->flist);
469 if (!error) {
470 error = xfs_bmap_finish(&args->trans, args->flist,
471 &committed);
472 }
473 if (error) {
474 ASSERT(committed);
475 args->trans = NULL;
476 xfs_bmap_cancel(args->flist);
477 return error;
478 }
479
480 /*
481 * bmap_finish() may have committed the last trans and started
482 * a new one. We need the inode to be in all transactions.
483 */
484 if (committed)
485 xfs_trans_ijoin(args->trans, dp, 0);
486
487 ASSERT(nmap == 1);
488 ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
489 (map.br_startblock != HOLESTARTBLOCK));
490 lblkno += map.br_blockcount;
491 blkcnt -= map.br_blockcount;
492
493 /*
494 * Start the next trans in the chain.
495 */
496 error = xfs_trans_roll(&args->trans, dp);
497 if (error)
498 return error;
499 }
500
501 /*
502 * Roll through the "value", copying the attribute value to the
503 * already-allocated blocks. Blocks are written synchronously
504 * so that we can know they are all on disk before we turn off
505 * the INCOMPLETE flag.
506 */
507 lblkno = args->rmtblkno;
508 blkcnt = args->rmtblkcnt;
509 valuelen = args->rmtvaluelen;
510 while (valuelen > 0) {
511 struct xfs_buf *bp;
512 xfs_daddr_t dblkno;
513 int dblkcnt;
514
515 ASSERT(blkcnt > 0);
516
517 xfs_bmap_init(args->flist, args->firstblock);
518 nmap = 1;
519 error = xfs_bmapi_read(dp, (xfs_fileoff_t)lblkno,
520 blkcnt, &map, &nmap,
521 XFS_BMAPI_ATTRFORK);
522 if (error)
523 return error;
524 ASSERT(nmap == 1);
525 ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
526 (map.br_startblock != HOLESTARTBLOCK));
527
528 dblkno = XFS_FSB_TO_DADDR(mp, map.br_startblock),
529 dblkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);
530
531 bp = xfs_buf_get(mp->m_ddev_targp, dblkno, dblkcnt, 0);
532 if (!bp)
533 return -ENOMEM;
534 bp->b_ops = &xfs_attr3_rmt_buf_ops;
535
536 xfs_attr_rmtval_copyin(mp, bp, args->dp->i_ino, &offset,
537 &valuelen, &src);
538
539 error = xfs_bwrite(bp); /* GROT: NOTE: synchronous write */
540 xfs_buf_relse(bp);
541 if (error)
542 return error;
543
544
545 /* roll attribute extent map forwards */
546 lblkno += map.br_blockcount;
547 blkcnt -= map.br_blockcount;
548 }
549 ASSERT(valuelen == 0);
550 return 0;
551 }
552
553 /*
554 * Remove the value associated with an attribute by deleting the
555 * out-of-line buffer that it is stored on.
556 */
557 int
558 xfs_attr_rmtval_remove(
559 struct xfs_da_args *args)
560 {
561 struct xfs_mount *mp = args->dp->i_mount;
562 xfs_dablk_t lblkno;
563 int blkcnt;
564 int error;
565 int done;
566
567 trace_xfs_attr_rmtval_remove(args);
568
569 /*
570 * Roll through the "value", invalidating the attribute value's blocks.
571 */
572 lblkno = args->rmtblkno;
573 blkcnt = args->rmtblkcnt;
574 while (blkcnt > 0) {
575 struct xfs_bmbt_irec map;
576 struct xfs_buf *bp;
577 xfs_daddr_t dblkno;
578 int dblkcnt;
579 int nmap;
580
581 /*
582 * Try to remember where we decided to put the value.
583 */
584 nmap = 1;
585 error = xfs_bmapi_read(args->dp, (xfs_fileoff_t)lblkno,
586 blkcnt, &map, &nmap, XFS_BMAPI_ATTRFORK);
587 if (error)
588 return error;
589 ASSERT(nmap == 1);
590 ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
591 (map.br_startblock != HOLESTARTBLOCK));
592
593 dblkno = XFS_FSB_TO_DADDR(mp, map.br_startblock),
594 dblkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);
595
596 /*
597 * If the "remote" value is in the cache, remove it.
598 */
599 bp = xfs_incore(mp->m_ddev_targp, dblkno, dblkcnt, XBF_TRYLOCK);
600 if (bp) {
601 xfs_buf_stale(bp);
602 xfs_buf_relse(bp);
603 bp = NULL;
604 }
605
606 lblkno += map.br_blockcount;
607 blkcnt -= map.br_blockcount;
608 }
609
610 /*
611 * Keep de-allocating extents until the remote-value region is gone.
612 */
613 lblkno = args->rmtblkno;
614 blkcnt = args->rmtblkcnt;
615 done = 0;
616 while (!done) {
617 int committed;
618
619 xfs_bmap_init(args->flist, args->firstblock);
620 error = xfs_bunmapi(args->trans, args->dp, lblkno, blkcnt,
621 XFS_BMAPI_ATTRFORK, 1, args->firstblock,
622 args->flist, &done);
623 if (!error) {
624 error = xfs_bmap_finish(&args->trans, args->flist,
625 &committed);
626 }
627 if (error) {
628 ASSERT(committed);
629 args->trans = NULL;
630 xfs_bmap_cancel(args->flist);
631 return error;
632 }
633
634 /*
635 * bmap_finish() may have committed the last trans and started
636 * a new one. We need the inode to be in all transactions.
637 */
638 if (committed)
639 xfs_trans_ijoin(args->trans, args->dp, 0);
640
641 /*
642 * Close out trans and start the next one in the chain.
643 */
644 error = xfs_trans_roll(&args->trans, args->dp);
645 if (error)
646 return error;
647 }
648 return 0;
649 }
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